Well bit



Nov. 24, 1936. HOWARD 2,061,657

WELL BIT Filed May 15, 1953 Fig. 1 Fig. 2

/n Venfor Jo/m fi Howard Patented Nov. 24, 1936 PATENT OFFICE .WELL BIT John H. I Howard, Huntington Park, Calif., 'assignor to Globe Oil Tools Company, Los Nictos, Calif., a corporation of California Application May 13, 1933, Serial No. 670,845 11 Claims. (01. 255-71) T is invention relates to a well drilling tool and relates more particularly to a well bit for use in the rotary method of well'drilling. It is a general object of the invention to provide a simple; practical well bit involving novel, improved and particularly effective roller cutters.

.-One class of rotary well drilling bit that has goneinto extensive use includes roller cutters mounted 'to rotate about axes inclined downwardly and forwardly relative to the direction of rotation of the drill and having longitudinally extending reaming blades and downwardly projector backing for supporting them against the outward dragging forces.

- It is an object of the present invention to provide a well bit including roller cutters mounted to rotate about axes inclined downwardly and rearwardly relative to the direction of rotation of the-drill so that the diamond substitutes or in-.

serts of hard cutting material on the edges of the teeth are not broken loose in the event that the cutters stop rotating. In accordance with the invention, the independently rotatable cutters are inclined downwardly and rearwardly so that the diamond substitutes 6n the edges of the cutting teeth are subjected to forces acting inwardly toward the axes of the cutters when the cutters stop rotating so that there is little or no tendency for the diamond substitutes to be torn from the teeth.

Another object of the invention is to provide a roller cutter for a well bit having novel and particularly effective reaming and cutting 'parts. An object of the invention is to provide a well bit including a roller cutter having reaming cutting parts that have an efiective cutting or shearing action on the formation on the sides of the well bore and that act to urge or feed the cutters downwardly into the formation. 1

Other objects and features of the invention will be best and fully understood from the following detailed description of a typical form and application'of the invention, throughout which description reference is had to the accompanying drawing, in which:

clined at slightly greater angles than the walls of Fig. 1 is a front elevation of,the bit provided by the invention showing it in one-quarter longitudinal cross section. Fig. 2 is a side elevation of the bit. Fig. 3 is a longitudinal detailed sectional view of one of the cutters and its mounting means, and Fig. 4 is an enlarged fragmentary detailed sectional view of a cutter taken substantially as indicated by line 4--4 on Fig. 1.

The bit includes, generally, a shank or body It] and cutter assemblies or cutter units II on the lower end of the body.

The shank or body IU of the bit includes an upper cylindrical portion l2 and two enlargements or bosses l3 carrying the cutter units H. The body In is adapted to be operated on the 5 lower end of a string of drill pipe, or the like, and a tapered screw threaded pin I4 is provided on the upper end of the portion i2 to facilitate connection of the body with a drillcollar or other part of an operating string. The bosses i3 constitute (the lower portion of the body In, and in accordance with the invention, the bosses are inclined downwardly and rearwardly relative to the forward direction of rotation of the bit. The

lower ends l5 of the bosses- I3 are fiat and are outwardly. 0 i

The cutter assemblies or cutter units II each 3 include a stem or pin i6 and a roller cutter I i rotatable on the pin. The pins [6 have longitudinally tapered upper portions [8 and cylindrical lower portions I9 for carrying the cutters IT. The tapered upper portions l8 of the cutter carrying pins are carried in correspondingly shaped openings 20 in the bosses iii. The openings 20 extend upwardly in the bosses from their lower ends l5 and their axes are inclined downwardly and rearwardly relative to the direction of rotation of the bit and are normal to the lower ends l5 of the bosses. In the particular case illustrated in the' drawing, the axes of the pin carrying openings 20 are inclined'at approximately 15 the tapered openings 2.0 so that the'upper pormerely join the openings 2E. The openings 20 are comparatively narrow and are longitudinally tapered or of diminishing cross section. Notches 22 are provided in the tapered portions i8 of the tions of theopenings Mintersect the openings 20, while the lower portions of the openings 2| cutter carrying pins to register with the openings 2 I ,where they intersect the openings 20. Retaining members or wedges 23 are driven throughthe openings. 2| to cooperate with the notches 22 in the pins 16. The inclination of the openings 2| and their taperingwalls causethewedges 23 to force the pins [6 upwardly into openings 20. -'-The retaining member or wedges 23 are comparatively thin and are sufliciently long so that their small ends project from the openings-2|. The projett-.-- 'ing small ends of the wedges 23 may be'distorted o'r bent over to prevent accidental displacement of the wedges. It will be apparent how the wedges 23 may be driven ,from the openings 2l to permit the removal of the cutter carryingpins' v I6 from the openings 20.

The lower portions l9 of the pins l6 for carrying thecutters I1 project downwardly from the lower ends [5 of the bosses l3, to rotat'ably support orcarry the cutters l'l at the-lower end ofthe. body .1 0. An annular radial flange 25 is'provided." on each pin [B on the upper end of its cutter carrying portion-l9. Wear plates and bushings Y are provided on the pins I 6 that are capable of beingjreplaced so that the .cutt'er' .-carrying pins their general configuration and have flat upper ends. Central longitudinal sockets 36 extend into the cutters I'I from their upper ends and receive:

the projecting portions i3 of the cutter carrying walls .for cooperating with the bushings 26 and flat bottoms or inner ends'foi' cooperating with the thrust plates 21. Enlargements 3i areprovided in the upper ends of the sockets 30 to receive the flanges 25. 7 Means is provided for removably. retaining the cutters I! on the pins 16. 55. the cutters to the pins. A lock ring or retaining and for transmitting longitudinal thrusts from ring 32 is attached to the upper end of each cutter H by cap screws 33. The attaching members or screws, 33- may be retained. against displacement byspot welding. The rings 32 project inwardly over the flanges 25 andwashers 34 are interposed between the rings 32 and'the flanges. The rings 32 positively .h ld the cutter l1 against downward movement on thepins l6 and are' adapted to transmit downward thrusts from' the cutters to the pins.

Each cutter ,I1 is provided .with a set or series of reaming cutting parts 40 and a plurality of 1 lower cutting parts or teeth 4! for acting .on the formation at the bottom or the well bore. The reaming parts 4ll are important features of the invention as they operate toyshear or cut away the formation at the side .walls of the well bore and to feed or urge the .cutters downwardly. The

reaming parts 40 are-in the nature of aplurality:

I of. longitudinally spaced annular ridges or sharp-f 'ened flanges surrounding theupper portions of the cutters I]. 'In the' particular embodiment of theinvention'illustrated in the drawing, the

reaming parts 40 are of equal diameter-and are continuous or unbroken. The tops OIMDQBI sides of there-aming parts 4t! are fiat and lie in planes substantially normal to the axes of rotation of the-cutters; [1. The lower sides of the reaming .parts 40 are inclined downwardly and inwardly and'almost jointhe upper sides of the reaming parts attheir peripheries to provide them with comparatively sharp cutting edges 40*,

When the bit is operated, the body In is rotated in a forwarder clock' wisedirection and the engagement of the cutters. H with the formation causes them toindependently rotate in a coun- .ter-clockwise direction. The reaming parts 40-; cut a thread or aplurality of grooves in the wall:

of the well bore and the rotation of the cutters I 1 causes the reaming partsto shearyofl the earth or formation between the thread or grooves they have formed by moving upwardly due to the rearward 'and' downward inclination of the cutters.

threadingor cutting of the-reaming parts '40 into the side wallsof the well bore tendstoforce or urge the cutters l-l downwardly so as to maintain the teeth 41 in effective cutting en? 'gagement; with the formation at the bottomof the bore. The inclined lower sides of the ream- ,ing parts-40 providesforthe ready. cutting. or

threading of the parts into the formation, whileshearing or cutting away the formation between thepthreads orcuts. I r

downwardly from thef'lo'wer ends of the cutters struetion, there is a plurali ty of circumferentiall'y Spaced teeth-"4| on each cutter l'I-j The. I

cutting teeth 4| extend longitudi nally oi the cut-- the lowermost reaming parts 40. The teeth 4| project radially outward-from the bodies of-the. cutters 11 and have outer cutting edges 42 inpins. The sockets 30 have cylindrically curved 'the-fiat-upper sides ofthe parts terminating in the outer-peripheral edges fare efiective in.

. .The lowercuttingjparts or'teeth' 4i project i I ters I1 and "have their upper ends spaced below 7 clined downwardly and slightly inwardly. The

lower portions of'the teeth 40 projectingifrom the lower ends of the cutters converge inwardly to-- ward the centers of the cutters and have their innerends 43 spaced from the central axes of the cutters. to engage the formation at the bottom of the well bore and operate to cause. rotation of the cutters. As the cutters l1 rotate about axes in clined downwardly" and rearwardly relative to of hard cutting material or diamond substitutes; 'Means, is provided for discharging circulation fluid from the lower ends of the cutters l1. A

central fluid passage extends downwardly into.

the upper end of the body I. Branch passages '51 extend downwardly and outwardly from the main passage 50 to the upper'ends of the open-' ings 20. The cutter carrying pins ii are tubular, being provided with central longitudinal openings 52. Enlargements 53 are provided in placeable plates 2] are provided with bossesor nozzle parts 54 which iaxtendupwardly into th The cutting teeth 4| are operable l the lower ends of the passages '52, and there-q enlargements 53. Restricted fluid openings 55 are provided in the nozzle portions 54 of the plates 21 to discharge the circulation fluid downwardly through central openings 56 in the lower ends of the cutters IT. The comparatively small nozzle openings 55 materially increase the velocity of the circulation fluid as it is dischargedunder pressure from the lower ends of the cutters. A central fluid discharge passage 60 of reduced diameter extends downwardly from the main fluid passage 50 to discharge from the lower end of the body It at a point between the cutters. The cutter mounting means and the fluid handling means are fully claimed in my divisional application entitled Well drilling tool, Sej m1 No. 14,118.

It is believed that the operation of the roller i the advancing and rotating cutters cause the reamingparts 40 to shear off the formation between the threads or cutsthus formed. The cut- ,ting engagement of. the reaming parts 40 with the formation urges or forces the cutters I1. downwardly. As the reaming parts 40 are continuous or annular and the wear is evenly distributed on their circumferences, they are very long wearing. The teeth M on the downwardly andrearwardly inclined cutters are effective in cutting away the formation at the bottom of the well bore as they are dragged over the surface of the formation during the rotation of the bit andcutters to successfully shear away the formation. In the event that the cutters l I stop rotating, the teeth 4| on the forward parts of. the cutters relative to the clock-wise direction of rotation of the bit have their, cutting edges leading so that the diamond substitutes 60 embedded therein are not likely to be broken loose. Due

to the inclination of the cutters ll, the teeth 4i on the rear of the cutters relative to the direction of rotation of the bit are clear of the bottom of the bore and are not subjected to any wear or dressing action in the event that thecutters stop rotating.

The combination of the annular reaming parts 40 and the radial circumferentially spaced teeth 4| on the downwardly and rearwardly inclined cutters ll produce a very rapid and eflicient cutting action, and insures the smooth steady operation of the bit. The cutter assemblies II are detachably connected with the body I0, by the wedges 23 so that they cannot become accidentally displaced during operation. The wedges 23 may be easily removed when it is desired to detach the cutter assemblies for replacement of the cutters or the like. The cutters I 1 may be charged downwardly and rearwardly from the causes considerable turbulence in the lower end of the. well bore. The circulation fluid discharging from the central outlet 60 effectively washes the reaming parts 40. The bit provided by the present invention is extremely simple and inexpensive of manufacture, and is rapid and effec- .tive in its operation.

Having described only-a typical form and application of my invention, I do not wish to be restricted to the form and application herein set forth, but wish to reserve to myself any modifications or variations that may appear to those skilled in the art or fall within the scope of the following claimsi Having described my invention, I claim:

1. A roller cutter for a well bit including, a-

body, cutting parts projecting from the lower end of the body and having cutting edges extending in substantially the same direction as the longitudinal'axis of the cutter, andlongitudinally spaced annular cutting parts on the body above the first mentioned parts and lying in planes substantially normal to the longitudinal axis of the cutter.

3. A well drilling tool including, a body to be rotated in a well bore, and a cutter projecting from the lower end of the body and rotatable about an axis inclined downwardly and rearwardly relative to the direction of rotation of the body, the cutter having longitudinally extending radial cutting parts projecting longitudinally from its lower end to engage the forma tion at the bottom of the well, bore and longitudinally spaced annular cutting parts projecting from its periphery to engage the formation at the side wallsof the'bore.

-4.'A well drilling tool including, a shank to be rotated in a well bore, and cutters carried by the about anaxis inclined downwardly and rear wardly relative to the direction of rotation of the body, the cutter including cutting blades projecting from its lower end and having cutting edges extending in substantially the same direction as the longitudinal axis of the cutter, and a series of longitudinally spaced circumferentially extending cutting parts for threading into theformation at the side wall of the bore to shear away the same and urge the tool downwardly.

6. A well bit including, a body to be rotated in a well bore, and two substantially diametrically opposite roller cutters projecting from the lower end of the body and rotatable about axes inclined downwardly and rearwardly relative to the direction of rotation of the body, each cutter including a plurality of longitudinally spaced cutting parts extending circumferentially around the cutter for acting on the formation at the side downwardly and rearwardly relative to the direction of rotation of the body and including longi- A i l0 rotatedin awell bore, and a roller cutter on the -'lower end of'tlie .body rotatable about an axis inclined downwardly and rearwardly relative to.

v tion at thebottom of the bore and reaming parts extendingcircumferentially around the cutter to be operable through their engagement with the wall ofthe well bore, the cutting edges of the cutting parts being comparatively sharp to thread into the formation.

'z. A well bit including, a body to be rotated in a well bore, and aroller cutter on the lower end of the body rotatable about anaxis inclined tudinally'extending substantially radial cutting parts projecting from its lower end, hard cutting.

inserts in tl e cutting edge portions of said parts, and annular peripheral cutting partslying in planes substantially normal to the axis of rotation or the cutter .to thread into the-formation at the sidewall of the well'bore.

8. A well bit including, a body adapted to be the directionof rotation of the bodyQthe cutter including cutting parts for engaging the forma ioimatibn'to urge the cutter downwardly.

- 9. A roller cutter for anearth boring tool including a substantially cylindrical cutter body, a multiplicity of longitudinally spaced annular cuttingparts surrounding andprojecting from the body, and longitudinally extending circum-" -ferentially spaced cutting blades projecting from' the body below said cutting parts, the blades having longitudinal cutting edges following a substantially cylindrical .pathl 10.-A cutter for an'earth boring tool including, a-cutter body adapted to rotate about a longitudinal axis, aplurality of spaced annular cutting parts extending around the body, and spaced axially extending cutting blades projecting out fwa rdl'y from the periphery of the body and down- I wa'rdly from its lower end, the outer edges of the blades being substantially the same distance from to urge the drill downwardly and shear away the formation, and spaced projecting axially extending' blades projecting beyond the lower end of the cutter-to act on the formation at the. bottom of the bore and having longitudinal outer edges spaced substantially the same distance from the -axis of rotation of the cutter as the cutting edges of the said "cutting parts. v

JQHN H. HOWARD. 

